What is the difference between Adobe Photoshop, Illustrator and Fireworks?

If you've ever ventured down the perplexing world of Adobe's graphic software, then you're probable confused by the difference between Photoshop, Fireworks and Illustrator. After all, at a first glance, they seem more or less the same eh? Yet, there are some fundamental differences.

First of all: Photoshop (CS5: US $699.00)

Photoshop is without doubt the most popular commercial Adobe Software. It's well renowned for incredible photo editing capabilities. Photoshop, being a raster graphics (also called bitmap graphics) application (like gimp and paint), it interacts directly with the pixels that compose the images. This makes it a great program for modifying already existing images since it can do virtually anything, but it isn't useful for the creation of graphics.

Now for Illustrator (CS5: US $599.00)

Illustrator may look similar to Photoshop at a first glance, but it is very different. Illustrator is a vector graphics program. This means that the image is not composed of pixels, but rather of mathematical constructs. Per example, in a raster graphic program like Photoshop, when you draw a line, it is simply a series of coloured pixels, whilst, in a vector program, a line is composed of two dots which are connected together by a computer algorithm. You can modify and move these dots as you wish.
Vector graphics are very well suited for the creation of digital imagery such as logos. They also provide a better print output since they are not resolution-dependent. If you wanted to stretch a raster image in order to print it to a very large sign, it would eventually blur or pixelate. This won't happen with vectors. The downside of vector graphics is that they can't be used to modify raster graphics, such as photos and scanned documents, and thus do not provide advanced photo editing capabilities.

Finally, Fireworks (CS5 US $299.00)

Fireworks is somewhat more confusing than the preceding programs. It's in some kind of "grey spot" between Photoshop and Illustrator. By "grey spot", I mean that it has both raster and vector options, but does not excel in neither of them.
At this point, you might be wondering, why would Adobe Systems take the time to create a third graphic software which has no clear advantage over Illustrator and Photoshop? Well, in fact, Adobe did not create Fireworks. They acquired it back in 2005 when Adobe bought Macromedia. Because of this, Fireworks integrates harmoniously with other former Macromedia products such as Flash and Dreamweaver. Fireworks is also much better for web graphics development. It supports better image compressions and gives you the option to create animated GIFS.

In Conclusion

Finally, if you're not looking for "hard-core" graphic capabilities, you might want to consider Fireworks. It has fantastic web support and a better price ;) Otherwise, those of you wishing to create really professional logos and print-oriented graphics will prefer Illustrator. And if you wish to make impressive photo editing, buy Photoshop.

P.S. before buying a multi-hundred dollar program, you might want to consider the free (open source) GIMP and Inkscape.